1. Field of the Invention
The present invention relates to an advance and retreat assist tool of an endoscopic treatment instrument, and an endoscopic system having this advance and retreat assist tool.
2. Description of the Related Art
An advance and retreat assist tool of an endoscopic treatment instrument (hereinafter, treatment instrument) assists the treatment instrument in advancing and retreating. Such advance and retreat assist tools have been disclosed in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2007-151595 and Jpn. Pat. Appln. KOKAI Publication No. 9-276212.
For example, in Jpn. Pat. Appln. KOKAI Publication No. 2007-151595, an endoscope has an advance and retreat operation portion provided at the proximal end portion of a grasping portion. The advance and retreat operation portion is provided coaxially with the central axis of the grasping portion. The advance and retreat operation portion has a rotation axis provided in a direction that intersects at right angles with the central axis of the grasping portion. The advance and retreat operation portion rotates around the rotation axis. The advance and retreat operation portion is toothed with the proximal end portion side of the treatment instrument. The advance and retreat operation portion advances and retreats the treatment instrument by the advance and retreat operation portion rotates. The grasping portion is grasped by the left hand of a surgeon, and the advance and retreat operation portion is rotated by the fingers of the left hand of the surgeon.
For example, in Jpn. Pat. Appln. KOKAI Publication No. 9-276212, a medical instrument introduction device is attached to a treatment instrument insertion hole portion so that the medical instrument introduction device is provided straight along the central axis direction of the treatment instrument insertion hole portion of a treatment instrument insertion portion. The central axis direction of the treatment instrument insertion hole portion is slanted relative to the central axis direction of the grasping portion. Thus, the medical instrument introduction device is provided aslant relative to the central axis direction of the grasping portion to depart from the grasping portion. The distal end portion of the medical instrument introduction device is close to the grasping portion, and the proximal end portion of the medical instrument introduction device is located away from the grasping portion.